Yahoo sued Facebook on Monday, the first major legal battle among technology giants in social media. But patent skirmishes are common in the tech industry. Is Yahoo simply firing the opening shots for a new battlefield?

ByDan Levine, ReutersMarch 12, 2012

Yahoo sued Facebook on Monday over patents. Pictured, a slide from Facebook Chief Operating Officer Sheryl Sandberg keynote address at Facebook's "fMC" global event for marketers in New York City, February 29, 2012.

Mike Segar/Reuters/File

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SAN FRANCISCO — Yahoo Inc sued Facebook Inc on Monday over 10 patents that include methods and systems for advertising on the Web, according to a copy of the lawsuit.

The lawsuit, filed in a San Jose, California federal court, marks the first major legal battle among technology giants in social media and a major escalation of patent litigation that has already swept up the smartphone and tablet sectors and high-tech stalwarts such as Apple Inc, Microsoft Corp and Motorola Mobility Holdings Inc.

Yahoo's patent lawsuit follows Facebook's announcement of plans for an initial public offering that could value the company at about $100 billion. A Facebook spokesman did not immediately respond to a request for comment on Monday.